The TDS® transformer dry-out system incorporates all the necessary features to allow a transformer to remain in-service while moisture from its insulation is effectively removed. The system is safe with several alarm features that shut the system off, isolating it from the transformer,in the event of any abnormal signal. The TDS5-1 unit provides a non-intrusive, cost effective and convenient method of maintaining transformers in a dry condition. In addition, once the transformer is dried, the system can be retrofitted with Activated Alumina cartridges to reduce acidity in the transformer oil. This flexibility allows increased oil processing application compared to heat and vacuum systems.

SYSTEM OVERVIEWThe TDS® oil processing system is designed to allow a transformer under load to dry itself out. A quantity of four part number SD-1107 Superdri® cartridges are installed in the filter vessel, through which oil is processed at a rate of 5 gpm. The filtering system removes dissolved water from oil to less than 10 ppm, and includes 1 micron nominal particle removal capabilities. The process does not affect dissolved gas in oil, and does not remove oil oxidation inhibitors. The system is complete with all components necessary to monitor the mechanical and electrical operating conditions of the unit. The system includes components to purge air during start up and after filter changes.

PROCESS OVERVIEWThe on-line dryout process is designed for safe, unattended, 24-hour operation. The system suction line is connected to the transformer bottom fill connection. The oil is then returned from the TDS® to a top connection valve. The number of cartridge changeouts required to dry the transformer insulation to an acceptable level and cartridge change-out intervals will vary according to moisture content and moisture transfer rate from the insulation to the oil. One set of Superdri cartridges will remove a minimum of 1.4 gallons of dissolved water from the oil. Periodic moisture readings, from both the inlet to and outlet from the system can be taken to determine the amount of moisture being removed and are also used to determine when cartridges should be changed.

Load Tap Changer Filter Systems

On-Line Oil Filtration for Load Tap Changer Compartments

The TP2 was developed in response to the utility industry’s desire to reduce operation and maintenance costs and increase system reliability. On-line oil filtration has proven to be an effective means of combating LTC problems. Tap changers retrofitted with a TP2 enjoy the following:

Consistent high oil dielectric strength

Extended maintenance/inspection intervals

Reduced contact wear and coking

Extended oil life

Reduced contact erosion via reduced restrikes during tap changing

The Velcon TP2 is recommended for installation on tap changers that:

Perform a high number of operations

Exhibit consistent sludging conditions

Have a high tap to tap voltage difference

Require frequent attention

Quality components and comprehensive design features have made the TP2 an industry standard for on-line filtration. All components are fully enclosed in a temperature controlled NEMA 4 cabinet. Operation of the unit is unattended and controlled by a user programmable timer. 3 gpm flow rate keeps turbulence in the reservoir to a minimum and allows for maximum filter life.